Leakage-indicating pavement joint



Patented Oct. 11, 1938 UNITED STATES PATENT OFFICE 2,133,059 yLEAKAGE-INDICATING PAVEMENT JOINT Walter 0.V Snelling, Allentown, lfa.

Application .March 30,

3 Claims.

indicate the presence of any open fissures or crevices through whichsurface water may penetrate, and will definitely mark the location ofsuch openings. It is well known that pavements areinjured by the seepageof water through openings in the joints between adjacent pavementblocks, and the later freezing of thiswate'r. Since water expands infreezing, any Water that finds its way .through openings, cracks orfissures in the pavement surface will produce, in subsequent freezing,expansive effects which produce great local pressure at the point ofexpansion. The pressure produced by water freezing beneath the pavementsurface tends to raise or heave the pavement blocks, and to producecracks and iissures in the pavement blocks, and these effects lead tothe deterioration of the pavement, since each crack or fissure that isproduced by the expansive action of ice beneath the pavement affords anew opening through which more water can penetrate to the pavementfoundation. a 30 My invention relates`- to improved pavement 4 joints,so constructed'that they automatically .indicate the presence ofopenings leading from the pavement surfacev to the pavement foundation,and definitely indicate the exact location o! 35 the surface openingthrough which water is nding its way to the lower portion of thepavementjoint. It will of course be evident that Athe cost of upkeep 'and repairof any pavement thus provided with an indicator that shows the exactreduced over the cost of upkeep of anyv pavement Vnot so provided.Ordinary-pavement joints require frequent and detailed observation overtheir entire length, in order that seepage openings may be promptlydetected and filled with sealing composition before great harm has beendone to the pavement by the action of water seeping through suchopenings, while pavements made in ac# cordance with my present inventiongive prompt and clearly visible indication of the 'presence of anyfissures or openings communicating from the surface `to the llowerportion of the pavement joint, and accordingly enable repairs to belmade only at these points of' leakage, the actual locatioi of theseepage opening being clearly and 1937, Serial No. 133,893` (Cl. 94-18)definitely indicated by clearly visible or detectable means. x

In the drawing, which forms a part of this specification, Figure 1represents a vertical section through a. pavement joint made inaccordance with my invention, and existing between two adjacent initialpavement block units. Fig

ure 2 represents a vertical section through a pavement joint made inaccordance-with my invention, the joint being a fissure or crack acrossor through a pavement block or unit.

In both gures, I represents the pavement block, which may be any type ofbitulithic, concrete or bituminous composition, the actual material ofconstruction of thev pavement block not .being of significance inconnection with my invention. 2 represents the underlying foundation ofthe pavement, which may be earth, sand, gravel or any other pavementfoundation material. 3 represents any porous joint filling material,such as sand, crushed stone, gravel or the like, and 4 represents anysuitable joint lling material, such as the usual asphaltic, tar, rubberor other joint filled tube or` other suitable type of train.. In YFigure 1, the train is shown in cross section as a paper tube filledwith indicating material, and present at about the center of the jointopening, andv in Figure 2 the train is shown as a painted streak ofindicator material present on the side walls oi the opening formed bythe joint fissure. 'I'he figures are not drawn to scale, and theindicator materialin particular is shown greatly enlarged, as comparedwith the other portions of the joint, in order to be clearly indicated.In4 the practice of my invention, the indicator material is a train ortube usually about one-tenth of an inch in diameter, or a tape orstreak, relatively very thin and narrow, and usually less than one-tenthof an inch in thickness. although `the width may vary from one fourth ofan inch to one or more inches if desired. p I` have discovered that whena suitable indicator substance, s uch as a water-soluble dye, awater-suspensible pigment, or a water-transportable indicating s stancesuch as fluorescene, escuiin, copper sulfate orthe like, is disposedlengthwise in a pavementI joint opening beneath a subsequently appliedpavement sealing composition, and preferably in association with acolumn of sand or other Water-porous material,

such indicator substance affords adesirableV means of indicating thepresence of openings in the pavement joint, communicating between the ofthe indicator substance becomes dissolved or.

suspended in the water which has thus seeped through the opening orssure at the pavement surface.l The action of vehicles passing over thepavement surface causes pressure to be exerted on the pavement blocks atintervals, and this periodic application of pressure to the pavementjoints causes the water to be alternately sucked in and expelled throughthe opening or fissure. As the water seeps in, it takes up a minuteamount of the indicator material, and as a portion of the water isexpelled as vehicles pass over the surface, this expelled Water,carrying the indicator substance, discolors or marks the pavement, atthe exact point of the location or presence of the opening or fissure.

As indicator materials I may use any suitabledye, such as croceinscarlet, soluble blue, Guinea green, Bismarck brown, or Water solublenigrosine, for example, or I may use any suitable water-insoluble finelydivided pigment material such as zinc oxide, titanium oxide, iron oxide,chromium oxide, chrome yellow, carbon black or the like, or I may use anon-dye indicator such as quinine sulfate, sodium iluorescene, esculinor vthe' like, which although not having dyeing properties shows itspresence by clearly visible or detectable indications. I prefer to usedyes forming colored kcompounds or lakes with concrete or cement, andcrocein scarletv forms an example of such a'dye.

I may place or dispose my water-transportable indicator lsubstance alongthe length of the pavement joint in many ways. I may for example moistena cord or tape with an agglutinant material, such as glue or acacia forexample, vand I may then coat the surface of such tape with crystals orpowder of the water-transportable indicator material and I may then laythis cord in the joint opening, before applying the sealing material.Instead of employing a cord or tape as the carrier of mywater-transportable indicator material, I may make a train of theindicator material, as by wrapping it in thin paper,

Y in much the same manner that ordinary firecracker yfuse is made bysurrounding a powder train with a paper tube or wrapping. I may apply mywater-transportable indicator material lengthwise directly to the lowerpart of the walls of the pavement joint, by means of a painting orspraying operation, or I may admix my indicator material with sand,crushed stone or gravel within the lower portion of the joint opening.My indicator material is preferably in the form of a continuous train orco1umn,vbut where individual crystals or particles of a pigmentor a dyeof high\coloring power are used, it will of `course not be necessarythat these individual .particles should be in contact with each other,and I may form a suitable train or column by spacing particles oraggregates of indicator material at desired distances apart, if this isdesirable. For example, I may dispose small isolated aggregates of dyeat intervals of about one inch, on a thin paper tape, in much the sameWay that small aggregates of explosive composition are disposed on papertape in making 4toy cap ribbons. The characteristic feature ofmyinvention is the disposing of an indicator composition in the form of acolumn or train, which may be either continuous or intermittent,lengthwise within the space defining a pavement joint Opening, andbeneath the lling or sealing composition, in such a manner that anyopenings, ssures, vcracks or even porous spots or imperfections in thesealing composition will be in-l dicated by the passageV of waterthrough such imperfections in the sealing composition and by.

the taking up of some of the indicator material by this seepage water,and by the subsequent deposition of this indicator material as a markiing at the location of the opening at the surface of the pavement in theforml of a. visible or detectable color or stain on the surface of thepavement.

By train as used in this specification and in the claims is meant alinearly disposed mass of material of the general nature of the powdertrain that is used in fuse. Such train may consist of particles of anindicator material continuously in contact, or of intermittentlydisposed particles or quantities of the indicator material at suchdistances apart as to afford a continuous or substantially continuousindicating means for surface water seepage. Such train may be disposedwithin a tube made of any water-permeable material, or may be in theform of a coating upon a cord or tape of paper or fabric, or may be inthe form of a coating spread or sprayed upon the solid walls of thejoint openwater. Dyes are soluble in water, and are held or carried insolution by water, but pigments are insoluble in water, and are held orcarried in suspension. My invention covers both finely dvided materialsthat are carried by water in suspension, and dyes and other indicatormaterials that are water soluble, and that are carried in solution bywater. I do not mean to cover by the 'term water-transportable anybroader meaning than that which is connoted by the joint terms ofwater-soluble and water-suspensible, the one relating to materials whichare soluble in water and which are carried by water in solution, and theother relating to pigment particles which are insoluble in water, butwhich are held or carried by Water in suspension, and that are or may becarried for such short periods of time as are involvedin the expellingaction of the pavement blocks during periods of expansion andcontraction, and particularly as a result of the passage of traffic overthe pavement blocks.

2,133,059 will afford readily visible or detectable signs or markingsupon the pavement surface, when such indicator material is carried tothe surface of the pavement by the means and in the way hereindescribed. Indicator materials are preferably dyes but may be substancessuch as iluorescene, which have no true staining or dyeing properties,but which are nevertheless clearly distinguishable by visual or byphotoelectrical means. The term indicating material also coverswaterinsoluble pigments. of any desired type. In the practice of myinvention I prefer to employ dyes' as indicating materials, and I preferto employ dyes thatA readily stain or dye cement or concrete, and thatmay be readily made colorless by appropriate chemical means, so thatrepair gangs may efface the markings left from a seepage, after havingrestored the water-resistance of the lling material at such point by arepair operation.

'I'he amount of indicator material thatI prefer to use in the practiceof my invention is determined primarily by the particular type ofindicator material that is employed, fluorescent materials being capableof use in the smallest quantity, dye materials being required insomewhat greater quantity, and pigments'being employed in still largerquantity. Using fluorescene, quinine, esculin or other fluorescentmaterials, I may use as little as one one-hundredth of a gram ofindicator material per foot of length of joint opening, under the mostfavorable conditions of use, as when leakage is detected at night bydirecting a strong beam of ultraviolet light (from which all visiblelight has been screened) along the lines of the joint. Using fluorescentmaterials, and employing ultraviolet light as a detecting means, it ispossible to determine leakage from joint openings treated in accordancewith my invention atl relatively high speeds of linear inspection, andif desired, photoelectric detecting means may be employed to pick up thefluorescent eiects produced by the beam of ultraviolet light. Where dyesare employed as indicating materials, I prefer to employ from-one-tenthgram to one gram of dye per foot of length of the joint treated, and

where vpigments or other similar materials are used as indicatingmaterials, I may use from one 3 gram to ten grams of pigmentper foot oflength of joint, depending upon the contrast strength or indicatingstrength of the indicator material employed, highly colored or highlycontrasting materials being capable'of being employed in relatively muchsmaller quantity than materials oiering less contrast with the normalappearance of the pavement or the joint surface.

In the practice of my invention, I nd that it is possible to injectadditional indicator material at any point of repair, and at the timethat such repair is made, as a means of restoring the amount ofindicating material that has been lost as a result of the action of theindicating material. Such injection or replacement of indicatormaterial, at a point where a pavement seal has been repaired, does notform, however, any paril of my present invention. Y

It will be evident that many modications may be made in the applicationof my invention, without departing from the scope of the disclosure ascherein made, and accordingly no limitations should be placed upon myinvention except such as are indicated in the appended claims.'

I claim:`

l. The process of forming a leakage-indicating pavement joint whichcomprises disposing Within the length of the lower portion of theopening between adjacent pavement units a train of. a

Water-transportable indicator material, and subsequently sealing suchtrain of water-transportable indicator material within the'joint fissureby means of an overlying mass of a pavement sealing composition.

2. A leakage-indicating pavement joint comprising a trainofwater-transportable indicator material disposed linearly within thelength of a I pavement joint and beneath a coating of a pave- A mentjoint sealing composition.

3. A leakage-indicating pavement joint comprising a train ofwater-transportable indicator material disposed along the length of lapavement joint, an associated parallel train of water-permeablematerial, and a joint sealing composition. overlying both thewater-permeable material and the water-transportable,indicator material.

WAL'I'ER o. sNELmNG.

